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American Institute of Electrical Engineers, Part II: Applications and Industry, Transactions of the

Issue 4 • Date Sept. 1958

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Displaying Results 1 - 19 of 19
  • The effect of quantization in sampled-feedback systems

    Page(s): 177 - 182
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    THE RAPID ADVANCE of digital computers and digital technology has resulted in recent years in the development of digital versions of practically every control system component. As a result, mixed systems composed of both digital and analog elements are becoming quite common. View full abstract»

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  • The sensitivity of the poles of linear, closed-loop systems

    Page(s): 182 - 187
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    One method of evaluating the constancy of dynamic response of a system is to determine how sensitive the poles of the system are to variations of the system parameters. If the sensitivity of a pole to one particular parameter is known, then for small variations of the parameter, the total change in the pole position may be easily computed. This method is used to show how dynamic error analysis in linear computer setups may be accomplished in a straightforward manner. The definition is also of some value as a general tool in the analysis of linear feedback systems. View full abstract»

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  • Use of phase space in transient-stability studies

    Page(s): 187 - 191
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    IN THE PAST FEW YEARS a great deal of interest has developed in the analysis of nonlinear systems. Much of this has been the result of the great strides taken in the field of control systems. However, nonlinearities have a way of appearing in many forms in many different types of systems. In fact, almost all systems when analyzed carefully have some degree of nonlinearity, and the linear representations are only approximations. In this paper some of the techniques that originated in control system work are extended to the analysis of a power system's stability, and in the process some new methods of analyzing nonlinear systems are presented. View full abstract»

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  • Statistical design theory for digital-controlled continuous systems

    Page(s): 191 - 201
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    IN A PREVIOUS PAPER,1 the basic theory and a procedure for optimum design of strictly digital systems were presented. In practice, however, strictly digital systems are few in number. Of far greater interest are digitally controlled continuous systems, in which a continuous plant is controlled by intermittently monitored and processed error signals. While only error signals at specific instants are used to control the system, the mean-square error averaged over all times is to be kept at a minimum. This paper develops the basic theory into a design procedure for doing this. The design procedure is no more complicated than that for a strictly digital system. View full abstract»

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  • Approximate analysis of the drag cup A-C tachometer

    Page(s): 202 - 209
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    Temperature coefficient, output voltage, and speed linearity error of output voltage are indicated in terms of relative changes in tachometer cup impedances when the output winding is essentially unloaded. By replacing the drag cup of a precision drag-cup a-c tachometer with one having a higher resistivity and a lower temperature coefficient of resistance, the following improved characteristics were observed: 1. The output voltage temperature coefficient was reduced to ¿0.06%/1 C (degree centigrade) 1/4 its former value. 2. Up to synchronous speed, the output voltage speed linearity error was reduced to ±0.05% of its synchronous speed output, 1/12 its former error. And 3 output volts per 1,000 rpm was reduced to 0.8 volt, 2/7 its former value. A simplified basic tachometer performance equation is derived, and curves are presented to show the required change in drag cup parameters to realize a specified performance. Frequency compensation is achieved by an R-L-C network in the tachometer excitation circuit. View full abstract»

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  • Practical air filtration for diesel locomotives

    Page(s): 209 - 212
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    VARIOUS forms of dirt and deposits in the engine and electric equipment of a diesel-electric locomotive are generally considered harmful. The purpose of filtration equipment is to remove as much of the dirt as possible, within economic limits. There is, however, a certain level of cleanliness beyond which it is not feasible to operate. View full abstract»

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  • An evaluation of the effect of dirt on diesel-electric locomotives

    Page(s): 212 - 215
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    THE EVALUATION of dirt costs on diesel-electric locomotives made in this paper is admittedly extremely approximate in nature because of the scarcity of factual data and the many assumptions used in lieu thereof. It divides the locomotive into three main categories: the diesel engine (with cost figures of fair accuracy), and electric apparatus and other apparatus with dirt costs of ¿order-of-magnitude¿ approximations only. Dirt costs are estimated on a total national basis, divided between cleaning and repair costs, with further subdivision as avoidable or nonavoidable. View full abstract»

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  • Wheel-slip detection in railroad braking

    Page(s): 215 - 219
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    THE INVENTION of the compressed air brake by George Westinghouse in 1869 was followed rather promptly by investigations of wheel slip and wheel slide. This is reported in the famous Galton Westinghouse Tests of 1878 and 1879.1 Prior to that time, wheel slip or slide was unknown on cars because the hand brakes used did not supply sufficient braking effort. Wheel slip frequently occurred during acceleration on locomotives, but this was very easy to detect due to the fact that the number of driving wheels was relatively few and they were usually connected in such a manner that all would slip in unison. Wheel slide in braking the locomotive was also not unknown since emergency stops were usually made by reversing the drivers of the locomotive and applying steam for compression braking, sometimes to the extent of spinning the drivers backwards. View full abstract»

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  • An analog computer study of a torsional vibrations problem

    Page(s): 219 - 227
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    TORSIONAL VIBRATION studies of simple mechanical systems are usually handled by methods which, while not difficult, often require the expenditure of considerable time when done by hand. The use of a digital computer shortens the time considerably. One method frequently used is the Holzer table calculations1 resulting in the determination of the natural frequencies of the system. Another method is a matrix solution of the differential equations of the system. View full abstract»

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  • Ventilating systems for railway traction equipment

    Page(s): 227 - 230
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    IN THE EARLY STAGES of the development of railway traction equipment the need for some form of ventilation became evident. This need increased with the continuing demand for increased output. As a result, cooling systems evolved from self- to forced ventilation. Their development was not, however, an unmixed benefit. Any ventilation tends to draw dirt, snow, moisture, and other contaminants into the machine, with harmful results. The undesirable effects may be reduced by design measures aimed at the following: 1. making the components more resistant to damage, 2. preventing the accumulation of foreign matter in critical locations, and 3. cleaning the air before it enters the machines The proper measures to employ in a given instance are determined by design, practical and economic consideration. View full abstract»

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  • Field experience with electrostatic precipitator on diesel locomotive engine air intake

    Page(s): 230 - 235
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    An experimental electrostatic precipitator was specially designed to fit the limited space in a diesel locomotive. Its effectiveness as an engine intake air cleaner and its practicality as a regular component in the locomotive were evaluated after two years of heavy freight service. View full abstract»

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  • Design of a drive system for a rotating arm

    Page(s): 236 - 241
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    THE SELECTION and preliminary design of a drive system for a unique test facility called a ¿rotating arm¿ was carried on simultaneously with the structural and mechanical designs. This rotating arm is required for directional-stability and maneuverability studies of high-speed submarines and surface ships. Large-scale models will be towed in circular paths with radii ranging from 12 1/2 feet to 120 feet and at submergence levels of as much as 10 feet. Final detail design of the electric machinery and control circuitry is contingent upon the results of exceedingly painstaking analog computer studies now partially completed. These studies are required of the manufacturer as proof of the adequacy of the machinery and its associated control circuitry for the intended application. View full abstract»

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  • Special power and lighting systems on aircraft carriers

    Page(s): 241 - 245
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    SINCE the introduction of aircraft carriers to the Fleet of the U. S. Navy their role has continually increased in scope as well as in importance. This has been due chiefly to advances made in aircraft and associated weapons and systems. These advances have had a direct effect on the electric power requirements of the ship service and emergency power system. Fig. 1 shows how ship service generating plants have continually grown, the CV4 in 1930 to the CVA(N) at the present time. The generating capacity of the CVA(N) is ten times greater than that of the CV4. Although this increased power demand has been necessitated by a number of factors such as higher ship's speeds, larger hulls, and more electronic gear, this discussion will cover only certain special power and lighting systems which are considered to be broad enough in scope to be treated individually. View full abstract»

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  • A differential reluctance measuring system and its application to model and ship testing

    Page(s): 245 - 249
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    A measuring system is described which has been developed at the David Taylor Model Basin for use in model and full-scale ship testing. The system utilizes transducers of the differential air-gap type, special designs of which permit measurement of torque or thrust in rotating shafts without the use of slip rings. The system includes instrumentation for direct recording and for visual or automatic digital readout. Accuracies of ±¿% or better are obtainable. View full abstract»

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  • Design features of large semiconductor rectifiers

    Page(s): 249 - 258
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    PARAPHRASING GERTRUDE STEIN, a rectifier is a rectifier is a rectifier. The many different service requirements, compounded by many economic factors, all influence the choice of design features available to the manufacturer. To obtain the best rectifier to fill specific requirements, one needs to make a careful evaluation of all the factors involved. View full abstract»

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  • Analysis of ignitron rectifiers for reversing-mill drives

    Page(s): 259 - 270
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    A REVERSING-MILL DRIVE for rolling-mill service for rolling blooms, slabs, or plates requires application of d-c motors operated under a special load cycle. The motor must be started, accelerated, operated under load, and decelerated many times as the metal which is being rolled is passed back and forth through the rolls. On alternate passes the motor is operated in the reverse direction. The time required for each pass is a few seconds. Typical motor ratings range from about 3,000 hp (horsepower) to about 12,000 hp. The required time for a speed change from base speed in the forward direction to base speed in the reverse direction is about 1 to 2 seconds. Several recent applications of this type have been built with a reversal time of 1 second. View full abstract»

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  • A static exciter for aircraft A-C generators

    Page(s): 271 - 277
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    HISTORICALLY SPEAKING, most aircraft a-c generators in this country have obtained their field excitation from a conventional d-c rotating exciter. This type of exciter is characterized by rotating windings and commutators to produce direct current. Slip rings are used to carry excitation current to the rotating field of the a-c generator. View full abstract»

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  • Lighting the modern commercial aircraft

    Page(s): 277 - 283
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    THE ADVENT of an aircraft wherein 115-volt alternating voltage is the primary power system offers the lighting engineer an opportunity to exploit a wider field of lighting devices. Previously, aircraft could use alternating voltage only at a sacrifice as it was heavy, expensive, and inefficient. However, it now occupies an advantage over 28-volt direct voltage for lighting use. It is the purpose of this paper to show how lighting research and alternating voltage contribute to the lighting of a modern commerical aircraft. View full abstract»

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  • The advantages of a pneumatic electric power system for high mach number aircraft

    Page(s): 283 - 288
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    AS THE SPEED of aircraft increases, the capability of the accessory power equipment to meet the added requirements imposed by such vehicles must also increase. The important need is for these capabilities to occur in time to be used on the aircraft. View full abstract»

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Aims & Scope

This Transaction ceased production in 1963. The current retitled publication is IEEE Transactions on Industry Applications.

Full Aims & Scope